(2020)<p>> Intervention daycares received segments of forest floor, sod, planters for growing annuals, and peat blocks for climbing and digging.<p>They covered the backyars with forest elements, and asked the children to play with it.<p>> The 28-day-long intervention that included enrichment of daycare center yards for microbial biodiversity was associated with changes in the skin and gut microbiota of children, which, in turn, were related to changes in plasma cytokine levels and Treg cell frequencies. These findings suggest that the exposure to environmental microbial diversity can change the microbiome and modulate the function of the immune system in children. Specifically, the intervention was associated with a shift toward a higher ratio between plasma cytokine IL-10 and IL-17A levels and a positive association between Gammaproteobacterial diversity and Treg cell frequencies in blood, suggesting that the intervention may have stimulated immunoregulatory pathways.<p>Doesn't this just say that being exposed to more, and perhaps different, microbials will trigger your immune system? There are lots of words, but my casual eyes don't read anything that would be non-obvious. Specifically, nothing in this study seems to look at long-term effects. It was a 28 day study without later follow-up. Is there a well-established link between what they showed and lasting immune system changes?<p>(Making the headline _technically_ true.)